How to naturally write an essay.

I would appreciate your guiding me on how to write an informal letter as an essay. The following is an attempt I have made so that you can tell me if it sounds coherent or not.

Dear Mum,

How's everything going there?

I really hope you are doing great these days that I've been away from home. As you already know,today's my third day of travel here in South America,and I felt a great wish to tell you how the trip's been coming out so far.First of all,however incredible it may seem,my connecting flight to Brazil was canceled when I arrived at the airport,so I had to stay in Buenos Aires on the first night.I was furious at the airline,and I was thinking of coming back home the next day and asking the travel agency for a refund,but after chewing it over for hours,I decided to go on and make the most of my adventure.To be honest, I was still disappointed on the first day,but after going out and getting to know the people, I started to stop regretting having lost the flight to Brazil! Here in Buenos Aires Locals are much more friendly than I actually expected. You can't imagine how pleasing it feels to see people who don't speak your lenguage making an effort to help you get something from the supermarket,take a taxi,find a post office location,and so on. But that's not all, Argentinians are excellent at cooking ! In fact,if I'd known Argentinian cuisine was so good,I'd have made plans to stay here from the beggining!

The letter goes on,but it's too long...